A HUMBLE, RELENTLESS, more or less continuous zoom shot taking forty-five minutes to traverse a Canal Street loft into a photograph pasted on the far wall, Michael Snow’s Wavelength (1967) provided twentieth-century cinema with a definitive metaphor for itself as temporal projectionand also burdened Snow with an unrepeatable masterpiece.

That the artist has a reputation as a painter, a sculptor, a musician, a video maker, and, mainly, a filmmaker gives “Michael Snow: Photo-Centric” a polemical thrust. At the very least, this highly concentrated exhibition supports the Bazinian assertion that modern art is essentially a reaction to photography (“manifestly the most important event in the history of the visual arts”). More specifically, the show suggests that Snow’s own strategies, regardless of medium, have been determined by his understanding of the photographic process.

Fashioned two years after Wavelength, the Polaroid self-portrait Authorization, 1969, is as perfect in its modest way as Snow’s perversely static motion picture: The artist made a rectangle of adhesive tape on a mirror and photographed himself within that frame, then pasted the photo in one corner of the taped rectangle and repeated the process until the photographs effaced his reflection. The subject of the work is the procedure via which Snow arrived at finished object; the author’s “signature” is inscribed as his gradually disappearing image. Snow has his predilectionsa prurient fondness for female nudes and elegantly deranged gridsbut his pieces are autobiographical in a highly specific way, typically concerned with the conditions of the work’s own making.

“Photo-Centric” is thematic rather than chronological, and much of the work dates from the early ’70s. Two big ideas dominate: the paradox inherent in the representation of volume in a two-dimensional field, and its oppositethe insistence that a photograph is also a thing. (Snow calls his photos “events-that-become-objects.”) The photographic pieces are sculptural. For instance, the assemblage of sixteen photos of various materials squeezed flat beneath Plexiglas plates that constitutes Press, 1969, is itself squeezed beneath a Plexiglas plate held in place by four large clamps, further enriching the pun.

Curated by Adelina Vlas, the show encompasses a half century of work, beginning with Four to Five, 1962, sixteen photographs of Snow’s early trademark, a life-size silhouette called the “Walking Woman,” positioned in various Toronto locations where it alternately (and sometimes simultaneously) functions as a chunk of negative or positive space. One of the most recent pieces, Paris de jugement Le and/or State of the Arts, 2003, is not dissimilar: This near-full-scale photograph of three naked women, backs to the camera and tan lines flaunted, up against a reproduction of Cézanne’s Large Bathers (from the PMA’s collection, as it happens) stages a competition for attention in the enforced democracy of the two-dimensional picture plane.

At first glance, Snow’s work looks formalist, but the basis is usually conceptual. (His motto might be William Carlos Williams’s “No ideas but in things.”) At the same time, his strongest pieces are perceptual. What you see is what you get. Like his sculptures (mainly simple, aggressively artless forms that are in some way interactive), Snow’s photographs can demand a physical shift in the viewer’s position. Crouch, Leap, Land, 1970, requires one to scrunch down under three suspended Perspex plates, thereby approximating the camera’s position as one peers up voyeuristically at three photographs of a nude woman’s leap that were themselves taken from beneath transparent flooring. It’s all a matter of perspective. The floor piece In Medias Res, 1998, is a photograph of a Persian carpet, as well as a bird’s-eye view of an escaped parrot in flight.

Many of the works in “Photo-Centric” consider what happens when something is photographedor painted and then photographed, or vice versa. A pair of timed cameras face off in Line Drawing with Synapse, 2003. The exhibition’s first big image is Times, 1979, an enlarged photo of a painting of a square; here the oblique camera angle suggests that the canvas is slightly rhomboid, provoking a subtle geometric disorientation.

Around the time he was working on Wavelength, Snow noted that “when you narrow down your range and are looking through just that narrow aperture of the [camera] lens, the intensity of what you see is so much greater.” The purestor most primitiveexample of this may be his 1982 Seated Sculpture, fashioned from several shaped steel plates: The viewer ducks inside to sit and contemplate a flat, black, rectangular void about seven feet away. It is a viewing device for induced tunnel vision or perhaps the cinema of negative space à la The Flintstones.

Eschewing as it approximates the cinematographic apparatus, Seated Sculpture is not included in “Photo-Centric.” (Neither is Snow’s 1975 book-object Cover to Cover, a portable static “movie” in which two cameras document the artist going about his daily routine from the front and behind or from opposite sides). But Digest, 1970, provides an even more dramatic and hands-on instance of cinema by others means. Snow filled a metal basin with various objects, periodically pouring liquid polyester over the assemblage and photographically documenting the process; twenty-three of these photos were then laminated and left in a pile for viewers to look through, and in so doing enact a virtual excavation of the basin. The effect is that of a reverse-motion time-lapse movie made material.

“Photo-Centric” itself leaves the impression that Snow, now eighty-four, wakes up every morning pondering the paradox of two-dimensional representation. Another artist might have gotten an entire gallery showeven a careerout of variations on nearly any one of these pieces. It’s confounding that none of New York’s major museums has yet given Snow a full-fledged retrospective.

“Michael Snow: Photo-Centric” is on view at the Philadelphia Museum of Art through April 27.

J. Hoberman’s Film After Film: Or, What Became of 21st Century Cinema? is recently out in paperback from Verso.